Both the blood and certain fats (chelev) of animals are forbidden for consumption. But there are differences, says the mishna, between the extent of the two.

While the ban on blood applies to both domesticated and undomesticated animals and to fowl, the ban on chelev is limited to domesticated animals alone. When it comes to the blood and chelev of sacrificial animals it is the other way around. Should one make use of such chelev for private purposes he is guilty of meilah embezzling from the Sanctuary. But if he makes such use of the blood of a sacrifice, he is not guilty of meilah.

In its explanation of why there is no meilah involved in using the blood (for fertilization purposes as was customary) after it has already been applied to the altar, the gemara states the rule that meilah cannot apply to anything which has already been utilized for the mitzvah for which it was designated.

This is an interesting rule because it is based on the exceptions to it. The shovelful of ashes which was daily taken from the altar by a kohen had to be placed at the side of the altar to be miraculously absorbed there and could not be appropriated for private use even though these ashes had certainly completed the mitzvah for which they were designated. The other exception dealt with the four garments which the Kohen Gadol wore for the Yom Kippur service in the Holy of Holies of the Beit Hamikdash. The Torah ordered that they be put away forever and be forbidden for any use.

Had the Torah wished us to derive from either of these cases a rule that meilah applies even after the mitzvah has been completed, it would have sufficed to make this point with one of them. The fact that this is found in two cases indicates that these two are the exceptions, and that the rule for all other cases is that there is no meilah in regard to something which has already completed its mitzvah role.

Liquefying foods is a practice which has become quite common in our health- conscious society. How does the transformation from a solid to a liquid affect the status of food as far as halacha is concerned?

A number of cases are discussed in our gemara:

1. Liquefied chametz drunk on Pesach carries the same penalty of karet (extirpation) as the eating of solid chametz.
2. Liquefied matzah eaten to fulfill the mitzvah of eating matzah on the first night of Pesach does not qualify for this purpose.
3. Liquefied chelev the forbidden fats of a domesticated animal carries the same penalty of karet as the eating of solid chalev.

The explanation of the difference between liquefied chametz and chelev on the one hand and liquefied matzah on the other is based on the terminology used by the Torah in regard to each.

Matzah is described (Devarim 16:3) as the "bread of affliction" so that the term "bread" even though it is a reference to matzah rather than leavened bread rules out the liquefied form of this substance.

In regard to chametz and chalev, however, the situation is different. Although in both cases the Torah prohibits the eating of such foods, which would indicate that this does not apply to drinking, when it comes to spelling out the penalty for their consumption the Torah states that "the nefesh (soul) which will consume it will be extirpated" (Shmot 12:19 and Vayikra 7:25). Nefesh, explains Rashi, indicates that the penalty of karet applies to the consumption of anything which brings comfort to a person, even if it is consumed through drinking, because this is considered as satisfying the needs of the nefesh.